Sewage pumping or lift stations are commonly used to pump sewage from one location to another. Two types of systems are commonly used. In one system, submersible pumps are employed and are directly submerged in a wet well which collects the effluent. The pump is energized to transfer effluent from the wet well to a processing station or to another collecting device.
In an alternate system, above ground pumps are used that sat atop the wet well. The pumps draw the effluent from the wet well and like the submersible pump application, transfer it to another location.
In the submersible pump system, the pumping station is somewhat immune to flooding. Since the pumps themselves are submerged, as long as electrical power continues to be maintained, the pumping station will function. In addition, since the pumps are submerged, pump operating noise is reduced.
In the case of the above-ground type installation, it has been found that the flooding of the station will generally cause failure in the pump or pumps and as a result even if power is maintained, the pumping station will be rendered inoperative. Moreover, after the flooding has receded, repairs must be made to the above-ground pump or pumps and related hardware to correct damage caused by the flood water. In the above-ground type station however, maintenance of the pumps can be easily effected during normal operation. The pumps are normally easily accessible and do not require specialized equipment to raise them from the wet well. However, since the pumps are located above ground, pump noise can be objectionable, especially in residential areas.
Submersible pumps, on the other hand, are very difficult to maintain. If a failure occurs in a pump, special equipment must be used to raise the pump from the wet well before it can be repaired. In addition, since the pump must be water-tight, repairs, maintenance and parts can be very expensive.